Flip-out device for fuses



p 19, 1944- c. w. BROWN 2,358,684

FLIP-OUT DEVICE FOR FUSES Filed Aug. 15, 1942 2 Sheets-Sheet l l 5 52; 222%, 22,, :22 Vl-t l 1 1 1 lll nwa V m Sept. 19, 1944. c. w. BROWNFLIP-OUT DEVICE FOR FUSES Filed Aug. 15, 1942 2 Sheets-Sheet 2 INVENTOR.

Z I v aw/ ,0 0 fi w I III! I I- L 1 I 1 I I Iii... I

Patented Sept. 19, 1944 FLIP-OUT DEVICE FOR FUSES Chester W. Brown,Milwaukee, Wis., assignor to Line Material Company, Milwaukee, Wis., acorporation of Delaware Application August 15, 1942; Serial No. 454,924

14 Claims.

This invention pertains to fuse cut-outs and has to do more especiallywith a device commonly known as a flip-out which is operative,immediately after the blowing of a fuse and in response thereto, quicklyto separate the arc electrodes within the fuse cartridge and,preferably, to wholly expel from the open end of the cartridge theelongate conductive leader constituting a severed part of the fuse link.

- The purpose underlying the use of such devices is to ensureextinguishment of the are within the fuse cartridge when the blow-out iscaused by a fault current of such little amperage that the ensuingexplosion is not, amply forceful to expel the leader or to bring about asufficient separation of the arc electrodes within the cartridge.

Modern dropout fuses are furnished factoryequipped with flip-outs whichfunction as above indicated; and the same is true with respect to somefuse cut-outs of the non-dropout type. But there are in use a great manyfuse cut-outs of the simple expulsion non-dropout type which are notequipped with in-built flip-outs, and it is to the equipping of thelatter that the present invention is more particularly addressed.

The primary object of the present invention is to provide an inexpensiveflip-out which can be utilized as an accessory to an expulsion fusecutout not otherwise so equipped.

Another and related object is to provide an accessory of theaforementioned'character which can easily and quickly be installed inthe field. Still another object is to provide a simple flipout which isinherently operative, when properly installed, to apply a uniformpredetermined tension to the fuse-link-which tension is determined atthe factory and not dependent upon the linemans judgment.

The unique features which characterize this invention can most readilybe adduced in conjunction with the detailed description of the twopreferred embodiments illustrated in the accompanying drawings, wherein:

Fig. 1- is a longitudinal sectional view of one form of flip-out deviceconstituting a preferred embodiment of the invention.

Fig. 2 is a longitudinal sectional view of a fuse cartridge of theexpulsion type shown equipped with the flip-out device of Fig. 1.

Fig. 3' is an elevational view, partly in section, of the lower end ofthe fuse cartridge of Fig. 2, illustrating the manner of operation ofthe flipout device of Fig. 1 in response to blowing of the fuse.

includes an elongate tube Fig. 4 is a longitudinal sectional view of analternative flip-out device representing a second preferred embodimentof the invention.

Fig. 5 is a longitudinal sectional view of a fuse cartridge of theexpulsion type, showing the flip-out device of Fig. being inserted.

Fig. 6 is an elevational view, partly in section, of the lower end ofthe fuse cartridge of Fig. 5, illustrating the flip-out device of Fig. 4installed and ready to operate when the fuse blows.

I shall describe first the showing of Figs. 1, 2, and 3 and thereafterthe showing of Figs. 4, 5, and 6.

The expulsion fuse cartridge of Figs. 2 and 3 I!) which may be of hornfiber or Bakelite lined with fiber or otherwise in accordance withwell-known practices. Tube H] has a bore l0 and is threaded externallyat its upper end to accommodate a tubular metal ferrule H, which isthreaded at l2 to receive a removable metal cap I3.

diameter of adapter 25 Gripped between cap [3 and the top of ferrule IIis a button-head contact member M which forms an integral part of theupper terminal I5 of a conventional strain-type fuse-link IS. Thefuse-link includes a fusible section ll, connected at its upper end toupper terminal I5 and at its lower end to a long flexible conductiveleader l8 which extends downwardly through bore l0 and upwardly from thebottom end of tube ID to a binding-post terminal l9, which includes ametal sleeve 20 and clamping screw 2|. Sleeve 20 embraces tube l0 and issecured thereto by a pin 22.

The flip-out device, identified as a whole by reference numeral 23,isshown, in Fig. 2, installed in the fuse tube and is separatelyillustrated in Fig. 1. It comprises an elongate flexible shaft 24consisting of a close-wound wire helix, anadapter 25 threaded to theupper end of the flexible shaft, a helical spring 26 telescopicallysurrounding and co-axial with the flexible shaft and secured at itsupper end to the adapter, a disc-like nut 21 threaded to the lower endof the spring, and a second disc-like nut 28 threaded to the lower endof the flexible shaft. The inside diameter of flexible shaft 24 is suchas to fit freely or, in any event, to permit insertion therethrough offlexible leader 18. It is not necessarily a close fit for the leaderalthoughit is so illustrated in Fig. 2. The outside should, preferably,be a fuse tube, but it may be all, so long as it clears free running fitin the a loose fit or no fit at the bore.

instantly without hindrance. aration is effected between the arcingelectrodes To install the flip-out the flexible leader is threadedthrough the bore of the flexible shaft and the latter, together with theadapter and attached spring 26 is inserted in the open end of the fusetube; and the spring is stretched and thus put under tension by pushingon the exposed end of the flexible shaft and on nut 28. This results inseating nut 21 against the end of the fuse tube, with nut 28 hearingagainst nut 2'|all as clearly illustrated in Fig. 2. The flexibleleader, being pulled taut, is secured at its free end to terminal I9 andit serves to anchor the flip-out in place and to retain it under tensionas will be evident from an inspection of Fig. 2.

The flexible shaft, while capable of being easily flexed in response toa laterally applied force, has the inherent property of being veryresistant to buckling when operating as a column. For

that reason the shaft will always remain erect against the tension ofspring 26.

The tension of spring 26 is applied through the flexible shaft and nut28 to flexible leader I8 and thus normally maintains the fuse-link underconsiderable tension-which tension is of definite amount, predeterminedat the factory and governable by appropriate selection of spring 25 orby appropriately varying the length of the flexible shaft, or both.

When fusible section II blows, the flexible leader is .no longer capableof restraining the flip-out and, in consequence, the leader is quicklyexpelledfrom the fuse tube by'the downward movement of the flexibleshaft and nut 28which, of course, is brought about by the contraction ofspring 26.

If flexible shaft 24 were not laterally yieldable it is not improbablethat the flip-out would be arrested in its action by the flexibleleaderdue to the abrupt bend in the leader where it emerges from thefuse tube and turns upwardly.

But the shaft being quite flexible in response to laterally directedforce is, capable of bending in the manner illustrated inFig. 3 wherebyto permit the inside end of theleader to move down within the cartridgeandv the arc is quickly extinguished, regardless of Whether or not theaccompanying explosionis sufficiently forceful to accomplish the sameend without theaid of the flip-out.

That part of the flip-out device which in Fig.

'3 is shown still within the fuse tube either drops,

out by gravity or is knocked out by the momentum of the downwardlymoving flexible shaft.

No doubt both are contributing factors.

In the alternative embodiment of Figs. 4, 5, and 6 the fuse cartridge isidentical with that of Fig. 2 and bears the same reference numerals. Theflip-out device is shown in detail in Fig. 4 and comprises a tubularmetal sleeve 29, ahelical spring 30,- and a metal ferrule 3|. Sleeve 29is internally threaded at by secured to the upper end of spring 39.Ferrule 3| is internally threaded to receive the lower end of thespring. .Sleeve 29 is frustro-conically flanged at its lower end to forma head 29a which serves to limit the extent to which the sleeve can beinserted into the fuse tube; and ferrule 3| is formed with a.frustro-conical skirt designed to fit within the tapered concavityofhead 29a, as shown in Fig. 6.

Thus a quick sep-' its upper endand there-.

In Fig. 5, sleeve 29 is shown pushed all the way?" into the fuse tube tothe full extent that head 29a is compressing spring 30; and flexibleleader l8 has i been pulled taut and anchored to terminal I9. When soanchored, the leader functions to hold spring 30 under compression.

The curled peripheral edge on head 29a provides a suitable surface aboutwhich to bend, without crimping, the flexible leader, and thefrustrO-conically flared skirt on ferrule 3| affords an angular surfaceover which the flexible leader can slide, and it avoids sharp turnswhich might tend to impede rapid movement of the spring and ferrulealong the leader when a blowout occurs.

It will be apparent that the flip-out of Figs. 4, 5, and 6 operatesaccording to the same principle as that of Figs. 1, 2, and 3 previouslydescribed. But here it is the spring rather than its companion memberthat is first ejected when a blow-out occurs. 7 I

The flip-out of Figs. 4, 5, and 6 comprises fewer parts-than that ofFigs. 1, 2, and 3'; but, on the other hand, sleeve 29 entails morecostly tooling than any of the parts of the first-described device.

It will be self-evident that each of the two above-described flip-outdevices can easily be installed by a lineman in the field, and that eachis quite inexpensive to manufacture and, therefore, can be replaced attrifling cost if lost as a result of a fuse blowout. Moreover, it willbe apparent that the tension applied to the fuse-link by the flip-out isdetermined independently of the linemans judgment-it being essentialonly that the device be correctly installed, which doesnot entail theexercise 'of discretionary judgment on the linemans part. .The\tensioncan be determined at the factory consonantly with the rating ofthefuse-link, and flip-outs of different tensions can, if desired, befurnished to suit the, various fuse-link sizes.

What is claimed is: v 1. A flip-out device comprising, in combination: ahelical compression 'spring, a rigid, tu-

bular sleeve telescopically encircling'and co-axial with said spring,one end only of said sleeve being frustro-conically flanged exteriorly,the periphwithin the frustro-conical concavity of' said.

flange when said spring is compressed and'there- .by to limit thedeflection of said spring compressively. V

2. A fuse linkflipout device for use in an'expulsion type fuse tube,said device comprising outer and inner telescopically related tubularmembers, one end of said outer member being anchored to thecorresponding end of said inner member, the opposite ends of saidmembers being free for relative axial movement, at least one of saidmembers including a spring and being expansible axially of the othermember, said other member being undeformable lengthwise as a result ofstressing of said spring including member axially, the inner of saidmembers providing an can bore 'therethrough and the outercf said membershaving anchoring means at its free end.

--'3'. A fuse link flipout device for use in an expulsion type'iusetube, said device comprising a movement, said spring member beingdeformable 'axially' 'and thus effective to apply lengthwisefst'ress't'osaid tubular member, one of said memhere being provided withan axial bore therethrough and the other member having anchoring meansat its free end.

4. A fuse link flipout device for use in an expulsion type fuse tube,said device comprising a tubular elongated flexible shaft, a helicalspring telescopically and coaxially related to said shaft, one end ofsaid shaft being connected to a corresponding end of said spring, theopposite ends of said shaft and spring being free for relative movementaxially of said shaft, and anchoring means on the free end of saidspring.

5. A fuse link flipout device for use in expulsion type fuse tubes, saiddevice comprising a tubular elongated flexible shaft consisting of aclose-wound Wire helix, a helical spring telescopically related to andencircling said shaft, one end of said shaft being connected with acorresponding end of said spring, the opposite ends of said shaft andspring being free for relative movement, said spring being resilientlyexpansible lengthwise of said shaft, and anchoring means attached to thefree end of said spring.

6. A fuse link flipout device for use in an expulsion type fuse tube,said device comprising a tubular elongated flexible shaft consisting ofa close-wound wire helix, a helical tension spring telescopicallyrelated to and encircling said shaft, an adapter securing one end ofsaid shaft to a corresponding end of said spring, the opposite ends ofsaid shaft and spring being free for relative movement, said springbeing resiliently expansible lengthwise and axially of said shaft, a nutattached to the free end of said spring, and a nut attached to the freeend of said shaft, said nuts being engageable upon expansion of saidspring to limit the extent of relative movement of said free ends in onedirection.

'7. A fuse link flipout device for use in an expulsion type fuse tube,said device comprising a helical compression spring and a rigid tubularsleeve telescopically encircling said spring, one end of said sleevebeing anchored to a corresponding end of said spring, the opposite endsof said spring and sleeve being free for relative movement, the free endof said sleeve being enlarged diametrically to serve as anchor means.

8. A fuse link flipout device for use in an expulsion type fuse tube,said device comprising a helical compression spring, a rigid tubularsleeve telescopically encircling said spring, one end of said tube beinganchored to a corresponding end of said sprin and the other end beingfrustoconically flanged exteriorly and free for movement relative tosaid spring.

9. In combination with a fuse including a fuse tube open at one end, apair of terminals one terminal being adjacent said open end, and a fuselink in said tube connecting said terminal and having a portionprojecting from said end and anchored to said one terminal; of a flipoutdevice removably positioned in said tube comprising outer and innertelescopically related tubular members disposed in the open end of saidtube, the ends of said members most remote from said open'end beinganchored together, at least one of saidmembers including a spring andbeing expansible axially of the other member, the inner member providingan axial bore through which saidlfuse link extends, and the outer memberhaving anchoring means engaging the open end of said tube, said fuselink normally holding said spring under stress, whereby upon rupture ofsaid link it will be expelled from said tube.-

lO; Incombination with'a fuse including a fuse tube open at one end, apair of terminals one .terminal beingadjacent said open end, and a fuselink in'said tube connecting said terminal and having a portionprojecting fromsaidopen end and anchored to said one terminal; of aflipout device removably positioned on said tube comprising a tubularmember and a helical spring member which are telescopically related anddisposed in the open end of said tube, the ends of said members mostremot from said open end being anchored together, the opposite ends ofsaid members being free for relative movement, the inner member of saiddevice having an axial bore through which said fuse link extends, andthe outer member having anchoring means engaging the open end of saidtube, said fuse link normally holding said spring under stress, wherebyupon rupture of said link it will b expelled from said tube.

11. In combination with a fuse including a fuse tube open at one end, apair of terminals one terminal being adjacent said open end, and a fuselink connecting said terminals and having a portion anchored to said oneterminal; of a flipout device removably positioned in said tubecomprising a tubular elongated flexible shaft loosely embracing saidfuse link, a helical tension spring telescopically and coaxially relatedto said shaft, an adapter securing one end of said shaft to acorresponding end of said spring, the opposite corresponding ends ofsaid shaft and spring being relatively movable, and an anchoring nut onthe relatively movable end of said spring engaging the open end of saidtube, said spring being expanded lengthwise and axially of said shaftand normally maintained expanded by said fuse link acting through saidshaft.

12. In combination with a fuse including a fuse tube open at one end, apair of terminals one terminal being adjacent said open end, and a fuselink connecting said terminals and having a portion anchored to said oneterminal; of a flipout device removably positioned in the open end ofsaid tube and comprising a helical compressing spring loosely embracingsaid fuse link, and a rigid tubular sleeve telescopically encirclingsaid spring, the end of said sleeve most remote from said open end beinganchored to the corresponding end of said spring, the other end of saidsleeve being enlarged diametrically and engaged with the open end ofsaid tube, said spring being normally held under compression by saidlink and sleeve.

13. In combination with a fuse including a fuse tube open at one end, apair of terminals one terminal being adjacent said open end, and a fuselink in said tube connecting said terminals and anchored to said oneterminal; of a flipout device removably positioned in said tubecomprising a helical compression sprin loosely surrounding said fuselink, a rigid tubular sleeve telescopically encircling said spring, theend of said sleeve most remote from said open end being anchored to thecorresponding end of said spring and the other end beingirusto-conicallyrfiared diametricallyv toward, the corresponding end ofsaid spring, said flared end engaging said open end of said tube, and afrusto-conically flared ferrule secured to said spring, said fuse linknormally-holding said ferrule nested insaid flared end of said sleeveand said spring'under compression.

- 14.. In combination with a' fuse including a fuse tube open at oneend, a pair of terminals one or which is adjacent said open end, and afuse link in said tube connecting said terminals and anchored to saidone terminal; of a fiipout .device removably positioned in said tubecomprising a tubular elongated flexible shaft consisting said other endof said helix and engageable with said anchoring nut for limiting theextent to which said spring may be expanded, said fuse link normallyacting through said helix to hold said spring expanded.

CHESTER W; BROWN.

